wayland: Move cursor surface role to meta-wayland-pointer.c

The wl_pointer assigns a role to a wl_surface, so it makes sense to put
the related logic there.

https://bugzilla.gnome.org/show_bug.cgi?id=744932

src/wayland/meta-wayland-pointer.h

@@ -27,9 +27,16 @@
 #include "meta-wayland-types.h"
 #include "meta-wayland-pointer-gesture-swipe.h"
 #include "meta-wayland-pointer-gesture-pinch.h"
+#include "meta-wayland-surface.h"
 
 #include <meta/meta-cursor-tracker.h>
 
+#define META_TYPE_WAYLAND_SURFACE_ROLE_CURSOR (meta_wayland_surface_role_cursor_get_type ())
+G_DECLARE_FINAL_TYPE (MetaWaylandSurfaceRoleCursor,
+                      meta_wayland_surface_role_cursor,
+                      META, WAYLAND_SURFACE_ROLE_CURSOR,
+                      MetaWaylandSurfaceRole);
+
 struct _MetaWaylandPointerGrabInterface
 {
   void (*focus) (MetaWaylandPointerGrab *grab,